In the field of double-barrelled shot-guns and sporting guns, whether the barrels are superimposed on one another or positioned side by side, there are already known various snap mechanisms with two hammers pivoting on an underguard and coordinated, respectively, with the firing pins corresponding to the two barrels. These known mechanisms have also a pair of snap rods for blocking the hammers in the cocked position, and a trigger that controls separately, by means of an inertial mass or rocker, the displacement firstly of one snap rod and then of the other nap rod, in order to unhook or release the two hammers in succession. In such known mechanisms, the trigger is connected to the inertial mass or rocker by means of an oscillating connector mounted on the tail of the trigger and displaceable height-wise together with such tail.
Similar snap mechanisms, also called monotrigger batteries, may include also selector means that permit the selective detachment or release firstly of the hammer related to one barrel and then of the hammer related to the other barrel, or viceversa, depending on the requirements of the user.
U.S. Pat. No. 4,091,556 discloses a mechanism of the type described hereabove, in which, according to an embodiment thereof, the oscillating connector for the connection of the trigger to the inertial mass or rocker is provided with steps interacting with the rods of the hammers and is displaceable in the transverse direction, so as to release firstly one hammer and then the other in a reversible sequence. In practice, the sequence of release of the hammers may be modified by moving the connector to the right or to the left through a sled-like control selector mounted on the inertial mass or rocker and positionable transversely thereon.
Such a construction is relatively complex. It calls for oscillations by the connector in two orthogonal directions, that is to say, in the longitudinal direction as well as in the transverse direction and implies some work by the inertial mass or rocker in order to mount the sled-like selector.